Reply to Letter to the Editor: “Evaluation of pressure-controlled mammography compression paddles with respect to force-controlled compression paddles in clinical practice”

by CRLPN Jeukens, JE Wildberger, MBI Lobbes

Evaluation of pressure-controlled mammography compression paddles with respect to force-controlled compression paddles in clinical practice

To the Editor,

Thank you for the opportunity to reply to the Letter to the Editor by C.A. Grimbergen and G.J. den Heeten regarding our recent publication, entitled “Evaluation of pressure-controlled mammography compression paddles with respect to force-controlled compression paddles in clinical practice” [1].

The aim of our paper was to evaluate a commercially implemented pressure-controlled paddle (Sensitive Sigma Paddle; Sigmascreening B.V.) in everyday clinical practice. So far, the value of pressure-controlled paddles had been shown in standardized settings, only [2, 3]. The implementation and training of the technicians was done forehand by the supplier (Sigmascreening), after which the paddle was used on one of our two mammography units in the clinical setting. On the other identical mammography unit, the use of a force-controlled paddle was continued. We analyzed the compressed breast thickness, compression force and compression pressure of the pressure- and force-controlled paddles in retrospect.

Grimbergen and den Heeten state that the compression forces observed were ‘very high’. Compression forces observed with the force-controlled paddles were in line with the force-controlled compression protocol described in the Materials and methods section. The European guidelines define no target forces [4]. The variation in compression forces observed (Fig. 3 of our publication) are not uncommon and were described in prior studies as well [5, 6].

We observed similar compression forces and compressed breast thickness for the pressure-controlled paddle in everyday use as well. We concluded there was no basis for preferring one paddle over the other in the way that the specific pressure paddle was implemented and introduced into our clinical workflow. This is in line with a recently published study reporting “…low scores of experienced pain during mammography, independent of the compression paddle used” [7], where the latter refers to a pressure-controlled paddle and flexible and rigid force-controlled paddles.
Grimbergen and den Heeten furthermore discuss the high compression pressures observed. As stated in the Materials and methods section and discussed in the study limitations, the pressure paddle itself does not indicate the pressure quantitatively. Therefore, the compression pressure needed to be calculated in retrospect, for which we used an algorithm published in literature [8]. This was done via an estimation of the breast contact area, which may have led to a deviation from the actual contact area and consequently the compression pressure applied. Our conclusions were therefore not only based on the calculated compression pressures, but these were merely used to confirm the observations based on compression pressure and compressed breast thickness.

We thank Grimbergen and den Heeten for the critical appraisal of our study. The paper itself as well as the discussion emphazise the value of vendor independent research in everyday’s practice to fully understand the potential (and the limitations) of a dedicated technical solution.